Flank Pain

Cannot miss / life threats
Cannot miss / life threats
Diagnostic flow β€” check first
Diagnostic flow β€” check first
  • Age >50 or vasculopath β†’ bedside aortic US FIRST (rule out AAA).
  • Reproductive-age female β†’ Ξ²-hCG before imaging (ectopic).
  • Fever + CVA tenderness β†’ UA + blood cultures β†’ think pyelo / infected stone.
  • Hematuria + colicky writhing pain β†’ non-contrast CT (stone protocol).
  • Pain out of proportion + AF / vasculopath β†’ consider renal infarct (CTA, LDH).
  • Right-sided pain + cough/dyspnea β†’ CXR for lower lobe pneumonia.
Differential diagnosis β€” checklist
0/22

Check off each diagnosis as you consider it. Tap the name for unique exam, lab/imaging clues, first-line confirmatory test, and management.

Urologic0/6
Vascular0/2
GI / hepatobiliary0/4
Gyn0/3
MSK / neuro0/4
Pulmonary0/3
Initial ED workup
Bedside0/4
  • Vitals + bedside aortic US (esp >50 y)
  • Pregnancy test
  • UA / urine dip
  • ECG if older
Labs0/5
  • UA + culture
  • CBC, BMP, lactate
  • Lipase, LFTs
  • Coags / type & screen if AAA suspected
  • Ξ²-hCG
Imaging0/4
  • Bedside US (aorta, hydronephrosis, gallbladder)
  • Non-contrast CT abd/pelvis (stone protocol)
  • CTA if vascular concern
  • Pelvic US for gyn cause
Initial management0/5
  • IV fluids
  • Analgesia (ketorolac if no contraindication; opioid if needed)
  • Antiemetic
  • Antibiotics if infected stone / pyelo
  • Urology consult for obstructed infected system
ED next steps
ED next steps
  • Vitals + bedside aortic US in any patient >50 before anchoring on stone.
  • Ξ²-hCG, UA, BMP, lactate, type & screen if vascular concern.
  • Non-contrast CT abd/pelvis (stone protocol); add contrast if AAA / abscess suspected.
  • Analgesia: ketorolac 15–30 mg IV (if no AKI/bleeding) Β± opioid; antiemetic.
  • IV fluids; antibiotics (ceftriaxone) if pyelo or infected stone.
  • Urgent urology consult for obstructed + infected system β†’ stent or nephrostomy.
  • Disposition: admit if septic, AKI, intractable pain, or stone >6 mm; OB/vascular consults as indicated.
Pearls / pitfalls
Pearls
  • First-time 'renal colic' in a patient >50 β†’ rule out AAA before anchoring.
  • Fever + flank pain + obstructing stone = urologic emergency (decompression).
  • Right lower lobe pneumonia can mimic flank/abdominal pain β€” get a CXR.